Scientists and researchers are onto a breakthrough in gene therapy after they cured a living mouse of hemophilia (essentially slower clotting). The study lead by Katherine A. High, a hematologist and gene therapy expert at The Children’s Hospital of Philadelphia, is the first successful case and could lead to genetic treatments for other diseases.

The therapy first uses enzymes called zinc-finger nucleases (ZNF), a sort of molecular scissor to cut targeted genes out of the DNA double helix. The researchers used the enzymes to neutralize the hemophilia mutation at the F9 gene, which they engineered in the mouse to mimic the human genome.

After the gene was cut out it was replaced with an unmutated form and after a little stimulation, the DNA repaired itself and integrated the new gene. The treated mouse began to heal in 44-seconds where as hemophilic mice need more than a minute to clot.

ZNF has been used for gene therapy before but this is the first treatment that has worked inside of a living patient rather than beginning on a petri dish. This surgically precise method could be used to treat a host of genetic conditions including sickle-cell anemia, nerve damage caused by diabetes, HIV, and AIDS.